This invention relates to release mechanisms for security bars, and particularly to release mechanisms that permit the security bar to be opened from the inside of the building and permit slight shifting of the security bar with respect to the wall to which it is mounted due to structural settlement.
In recent years, there has been increased concern over security of persons and property. One result of this concern is the increased use of security bars or grills over openings, such as windows and doors of dwellings and other buildings. In typical installations, security bars are mounted directly to the exterior wall surface of the building and serve to prevent entry through the opening.
There is increasing concern that the security bars also prevent emergency exit through the opening, such as in the event of fire. For this reason, releasable security bars have been developed permitting the occupant to quickly release the bar from the window in the event of an emergency. These quick release mechanisms usually employ rods that are attached to the security bar and extend through shaft openings in the wall of the building to be locked inside the building. The occupant, desiring to escape through the window, unlocks the rod to push away the security bar. The security bar may be hinged to the building so that it may be swung away from the opening when the release mechanism is unlocked.
One problem associated with prior quick release mechanisms concerns structural settlement. More particularly, building settlement due to normal settlement, seismic activity and other causes, caused misalignment of the security bars to the building structure. Consequently, the force necessary to operate the release mechanism increased, rendering it difficult to release the security bar in case of emergency. Accordingly, there is a need for a quick-release mechanism for a security bar that is not affected by structural settling.
Another problem with prior release mechanisms is that they could not be opened from the outside by rescuers and other emergency personnel. Instead, prior release mechanisms required operation by the occupant inside the structure to release the security bar. If the occupant was incapacitated, it was not possible for rescuers tom easily remove the security bars. Accordingly, there is a need for a security bar release mechanism that automatically releases the security bars in the event of emergency conditions, thereby permitting rescuers to open the security bar from the outside of the structure.
Another problem of prior release mechanisms is that many such mechanisms required removal of pins or turning of latches to operate which confused users during emergency conditions. There is a need, therefore, for a release mechanism that is simple to operate during emergency conditions.
According to the present invention, a lock mechanism releasably locks a security bar over an opening through a wall, adjacent an outside surface of the wall. Broadly, the lock mechanism includes a housing for mounting to the wall adjacent the opening. An engagement mechanism is coupled to the security bar. A keeper member in the housing is movable to selectively engage a lock surface on the engagement mechanism to restrain the engagement mechanism from movement relative to the housing; the engagement mechanism being allowed to move unrestrained relative to the housing when the keeper member does not engage the lock surface. A manually-operable latch mechanism in the housing moves the keeper member out of engagement with the lock surface.
One aspect of the invention resides in a receiver tube forming a passage between the housing and the outside surface of the wall. The engagement mechanism extends through the receiver tube without engaging the receiver tube so that the engagement mechanism is laterally moveable in the receiver tube so that the release mechanism is unaffected by settling of the structure.
More specifically, the lock mechanism releasably locks a security bar over an opening through the wall and adjacent a first surface of the wall. The housing is mounted in the wall adjacent the opening such that respective portions of the housing are exposed to the opposite first and second surfaces. The engagement mechanism includes a cable having a first end for connection to the security bar and a second end connected to a receiver. The receiver has a lock surface. A plunger extends from the housing through the second surface of the wall and includes a cam surface having first and second portions. The keeper includes a roller in the housing engaging the cam surface on the plunger. The keeper is movable from a first position to a second position when the plunger has moved to an unlock position. When in the first position, the roller engages the first portion of the cam surface which forces the roller into engagement with the lock surface of the receiver so that relative movement between the housing and receiver is restrained. When in the second position, the roller engages the second portion of the cam surface which permits disengagement from the lock surface of the receiver so that the receiver and cable are free to move relative to the housing. A bias spring biases the plunger to a lock position in which the keeper engages the first portion of the cam surface so that the roller engages the lock surface of the receiver and the security bar is locked over the opening in the wall. Operation of the plunger to the unlock position moves the roller to its second position to unlock the security bar from the opening in the wall.
In one form of the lock mechanism, the housing includes a cage, and the roller comprises a rod supported within the cage so that when the plunger is in its lock position, the first cam portion on the plunger engages the rod to sandwich the rod between the cage and the lock surface. When the plunger is in its unlock position, the rod is biased by the cage into the second receiver portion on the plunger free of the lock surface on the receiver.
In another form of the lock mechanism, a slide is supported by the housing and has a surface for engaging the plunger. The slide is movable to operate the plunger to move the keeper from its first to its second position. A second bias spring biases the slide to operate the plunger, and a removable restraint engages the slide to restrain the slide from operating the plunger. An external actuator is operable to remove the restraint from engagement with the slide so that the slide operates the plunger to move the keeper to its second position. In various forms, the external operator may be a smoke detector, a heat detector and/or a radio receiver operated by remote control from an authorized source, such as a fire station.